I am vitally interested in supporting real solutions that permit a rapid transition away from fossil fuels, especially coal (oil will, at least in part, take care of itself). If the conclusion is that wind/solar cannot meaningfully facilitate this transition, why bother to promote them? Now, I should make one thing quite clear. I am not AGAINST renewable energy. If folks want to build them, go for it! If they can find investors, great! Indeed, I’m no NIMBY, and would be happy to have a conga line of huge turbines gracing the hills behind my home, just as I’d be happy to have a brand spanking new nuclear power station in my suburb. But why should I promote something I have come to consider — on a scientific and economic basis — to be a non-solution to the energy and climate crisis? That doesn’t make sense to me. So, to the ‘options':

1. Coal with CCS — doomed to failure. Why? Because the only thing that is going to be embraced with sufficient vigour, on a global scale, is an energy technology that has the favourable characteristics of coal, but is cheaper than coal. CCS, by virtue of the fact that it is coal + extra costs (capture, compressions, sequestration) axiomatically fails this litmus test. It is therefore of no interest and those who promote it can only do so on the basis of simultaneously promoting such a large carbon price that (a) the developing world is highly unlikely to ever impose it, and (b) if they do, CCS won’t be competitive with nuclear. CCS is a non-solution to the climate and energy crises.

2. Natural gas has no role in baseload generation. It is a high-carbon fossil fuel that releases 500 to 700 kg of CO2 per MWh. If it is used in peaking power only (say at 10% capacity factor), then it is only a tiny piece in the puzzle, because we must displace the coal. It it is used to displace the coal baseload, then it is a counterproductive ’solution’ because it is still high carbon (despite what the Romms of this world will have you believe) and is in shorter supply than coal anyway. Gas is a non-solution to the climate and energy crises.

3. The developing world lives in Ted Trainer’s power-down society already, and they are going to do everything possible to get the hell out of it. The developed world will fight tooth an nail, and will burn the planet to a soot-laden crisp, rather than embrace Trainer’s simpler way. Power down is a non-solution to the climate and energy crises.

4. It is nice to imagine that renewables will have a niche role in the future. But actually, will they? They don’t have any meaningful role now, when pitted in competition with fossil fuels, so why will that be different when pitted fairly against a nuclear-powered world? I don’t know the answer, and I don’t frankly care, because even if renewable energy can manage to maintain various niche energy supply roles in the future, it won’t meet most of the current or future power demand. So niche applications or not, renewables are peripheral to the big picture because they are a non-solution to the climate and energy crises.

5. Smart grids will provide better energy supply and demand management. Fine, great, that will help irrespective of what source the energy comes from (nuclear, gas, coal, renewables, whatever). Smarter grids are inevitable and welcome. But they are not some white knight that will miraculously allow renewable energy to achieve any significant penetration into meeting world energy demand in the future. Smart grids are sensible, but they are not a solution to the climate and energy crises.

So, it’s down to nuclear, as detailed here. To some, the above may sound rather dogmatic. To me, it’s the emergent property of trying my damnedest to be ruthlessly pragmatic about the energy problem. I have no barrow to push, I don’t get anything out of it — other than I want this problem fixed. I don’t earn a red cent if nuclear turns out be the primary solution. I don’t win by renewables failing. The bottom line is this — if this website is looking more and more like a nuclear advocacy site, then you ought to consider why. It might just be because I’ve come to the conclusion that nuclear power is the only realistic solution to this problem, and that’s why I’m ever more stridently advocating it. This is a ‘game’ we cannot afford to lose, and the longer we dither about with ultimately worthless solutions, the closer we come to endgame, with no pawn left to move to the back row and Queen.

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62 Comments

Barry, I like the choice of topic categories in the new set of tabs at the top of the page.

I think you should add your ‘Necessary Interlude’ post to the list above, as your response to ‘Mark’ in it is possibly the most concise and direct statement of why renewable energy will not replace coal that I’ve seen on this blog. Maybe even break it out as a summary for this tab.

Consumerism and economic growth are inextricably linked, if we massively reduce our fossil fuel consumption ( which is clearly required ) and replace it with a similar capacity of nuclear generated electricity. What then ?

Still growing at 2 -3 % annually, ( doubling in 25 – 35 years ) – that’s without popultaion growth and increasing 3rd world demand ( and the 3rd world has every bit as much of a right to consume the same ).

There is a problem with this and nuclear power won’t fix it.

If you look at a future with significantly less consumption, energy efficiency and sensible resource use, then renewable enrgy becomes a more attractive, affordable and sustainable solution.

cant find a emailadress or a contact field here so this is my only way to make myself heard. though its totally off topic, hope you dont mind…

In the autumn I have been working together on a project with KSU (nuclear safety and education) which aims to make YouTube videos of their brochures, first out is “ionizing radiation”. Swedes target audience is between 13 to 35. The goal with movies is to spread knowledge about the subject in a simple, flexible format that is easy to absorb.

We are so happy with the result that we now want to get them to the public, in my search for pages that would fit, I turned on your. I thought it might fit.

And with the exception of some nuclear power proponents, renewable energy deniers are generally also climate change deniers.

If they cannot refute a particular observation by rational argument, they try to cast doubt on the result by introducing irrelevant material. They look for molehills in renewable energy systems and blow them up to mountains. They are masters of the 10% truths: taking a few facts and then spinning them into stories that convey the opposite impression from the logical implications of those facts. They insinuate arguments rather than state them clearly and unambiguously. Then, when questioned incisively about their insinuations, they back off and shift ground.

I’d assert that these statements are applicable to the renewable energy advocates rather than to the critics of renewable energy and the proponents of nuclear energy (which are often not the same).

My concerns with wind and solar power are that they are totally uneconomic, require huge subsidies, distort the market, do not cut emissions significantly if at all, and they are diverting our focus from what are the most ecomically viable ways to provide clean electricity.

I made the following comment over at Crikey, reproduced here for those without the benefit of a subscription:

I do wonder where Diesendorf gets his data from. I have read this “in Australia a square 30km by 30km, filled with solar collectors and installed on marginal land, could provide all of current electricity” before but just let it go as clearly impractical. But it is also wrong. Even Desertec said it was 50km x 50km and I thought they were being optimistic about future conversion efficiency. This is mastery of 0% truth.

The wind cost he refers to does not include grid connection, transmission and firming (standing reserve requirements). He likes to say the firming requirements will be supplied “with a little intermittent back-up from gas turbines” By his own admission in his book, a little is 25% of the wind installed capacity. So 1,000 MW of wind needs 250 MW of gas back-up standing around in case it is needed. But the 1,000 MW of wind power could have been supplied by 300 MW of gas in the first place so we have invested in 1,000 MW of wind to save 50 MW of gas. Sure the gas will not be needed all the time so there will be GHG savings but at considerable cost. Of course the other response is if wind is truly cost competitive why do we need a RET scheme?

“The prices of more expensive forms of renewable electricity, solar photovoltaics and concentrated solar thermal, are declining steadily as their markets expand, and are likely to become competitive with nuclear (whose capital cost has been escalating rapidly) by 2020.”

Isn’t that phrase “are likely to become” one of those “misleading assertions [that] are repeated, as if repetition of a falsehood somehow makes it true”?

The 20% wind energy for Denmark might be formally true, but the deeper question you should be asking is: Has this additional generating capacity actually displaced any baseload coal-fired power stations? I’ll leave you to work out the answer.

Mark refers to those who have critically and quantitatively analysed our possible carbon free energy futures and come to the conclusion, without prejudice, that renewable power generation systems simply can not meet Australia or the world’s energy demands, as “renewable energy deniers”. This is a transparent ploy to associate thoughtful quantitative analysis with the cranks denying climate change. It is an underhanded and rather dishonest tactic, in my opinion, which I doubt will wash with many readers. Its name calling, when the issue demands quantitative analysis and integrity t what the data is saying.

Far from being ‘myths’, the four problems Mark identifies are real problems, serious problems, with the engineering of a practical renewable generation system. The engineering shortcomings of renewable energy flows and the systems designed to harvest them are glossed over in the various plans proposed to get us to a renewable-only future. The gaps that are glossed over inevitably get plugged with fossil fuels, as in the example Barry Brook gives above.

We simply cannot commit to a one time infrastructure investment of tens of billions of dollars over decades, only to discover that we’ve wound up with a power system that is still critically dependent on fossil fuels and is a savage greenhouse emitter. That is where renewable energy will take us.

Fortunately we have a choice. The nuclear power plants China is now punching out by the dozens, quickly and cheaply, are safe, clean, carbon free power. We need them here, now. Or we could follow the Indian model, taking us to a virtually inexhaustible thorium fuel cycle. And Generation IV designs, such as the integral fast reactor or the liquid fluoride thorium reactor, will give more and better options in the future.

Ideas in science and engineering often seem very unlikely at their genesis. They often need strong willed, determined advocates to see their development through the difficult early development phase. Mark has been this advocate for renewable power, and is to be applauded for his efforts.

But there also comes a point where its clear the problems are real, they’re not going away, and that its time to let go. Renewable energy is at that point now, and this is becoming clear to people who have an investment in solving the climate (or peak oil problem), but no investment in the technology used to do so. The renewable dream officially died with the failure of Danish and German wind, Spanish solar, Ausra, and other large scale attempts that confirmed the validity of these critiques of renewable systems.

I still can’t believe that people who care about climate change can still, with a straight face suggest that ‘nuclear is the only way’.

Central to the concept of caring about climate change is the consequence of Intergenerational Equity; not wanting to stuff things up so that those that come after us have a harder time of it.

Nuclear power flat out fails on this count. The levellised costing numbers produced by the IEA that Mr Duffet quotes so religiously have a serious methodological flaw; they are based on Net Present Value calculations, and they ‘include decomissioning’.

NPV calculations are at direct odds with intergenerational eqity. The NPV methodology is based on the fact that money is worth more now than in the future and dinishes future costs compared to holding that money as an investment until then. Using the discount rate that the IEA uses a cost in 30 years of 1 billion dollars becomes just $63m. Make it 60 years and the future decomissioning cost of a nuclear power plant is $3million dollars. Does that sound reasonable to you?

If cost is so important, I need nuclear advocates to answer 3 questions:
1. What is the future cost of decomissioning? How can you be certain of this? How many plants have been decomissioned to date?
2. What is the future cost of long term storage?
1 and 2 are strongly linked as the radioactive waste from the desomissioning will need to be stored soewhere.
3. Explain to me how nuclear power can lower greenhouse emissions in the next 10 years; next 20 years. Ziggy Switkowski, nuclear energy fan-boy to the stars doesn’t think 1 plant, thats 1 plant, could be built before 2030. Why is Ziggy wrong?

Barry; I think it would be more honest if rather than saying ‘the awesome and totally objective Brave New Climate’ you said ‘my website’. Just a thought.

Further, I’ve looked at your TCASE series and I find it a load of crap and have pointed out flaws in it previously. If you are serious about peer review, I will do a full analysis of all your numbers and state why I disagree with them. Only if you promise to publish my rebuttal on your website. Somewhere where people can see it.

Eponymous, I’m not aware that you’ve commented here before – perhaps you did so under a different alias beforehand. You are most welcome to post comments/critics of my calculations and/or assumptions in the relevant TCASE posts.

Intergenerational equity is already addressed in nuclear power by considering how tiny the waste stream is compared to other energy sources. This is already true with thermal reactors, and absurdly true with fast reactors and LFTRs. Decommissioning is a standard industrial process, albeit with some unique complexities, and there is plenty of experience in doing this, for many research reactors and a fair number of commercial power reactors.

As to your point about how lower power will lower emissions within the next 10 or 20 years, it will worldwide, and won’t do much if anything for Australia. But what, pray tell, will?

Yeah Barry, I have had some discussions with you before, under my real name. For reasons of employment security I can only comment on this stuff under a pseudonym. I’m not happy about it either.

Just to make sure we’re not dodging questions of each other, I don’t think you’ve answered my criticisms.

‘Tiny waste stream’ is not a helpful answer. How much waste per reactor, per year and price per unit mass would be an instructive start. All I want is to create a level playing field in the levellised costing. I know of no waste stream from either geothermal or solar thermal power plants. Am I missing something?

I want to know of current waste storage facilities, how much they cost to run and how ongoing security issues are addressed.

WRT decommisioning, I want to know of previous examples of plants that have been decomissioned, how much that cost and how the waste was stored.

I don’t know how your final statement is helpful, nor do I understand what your point is. You agree that nuclear will make no contribution in the next 10-20 years. Surely this is a problem if you’re concerned about lowering emissions?

In Australia, despite how much people hate it, wind is likely to be the biggest contributor in the foreseeable future. It is mature thanks to European investment and just about cost effective, even without a price on carbon. I also expect that domestic solar will make a contribution of sorts, geothermal could make a significant contribution before 2020 and I hope some solar thermal plants are built by then.

I am not opposed to nuclear per se. But, I think you’re wasting your time and even being a bit silly trying to hold out hope for it in Australia. We have no nuclear expertise nor industry in Australia at the moment. The whole, complicated business needs to be built from the ground up. Also, Federal laws need to be changed. Why so much love for nuclear when there is almost no chance it will make a contribution in the next 20 years? Why not just move to France and see your dream become a reality?

Eponymous, if you are dissatisfied with my very brief response above, then I strongly suggest that you read other posts on this blog, in which I and others have taken pains to answer your queries above, in detail. The search box is helpful for locating relevant information.

If you do want to continue this discussion, it’s probably best to do it in the Open Thread or in a relevant TCASE post.

NPV calculations are at direct odds with intergenerational eqity. The NPV methodology is based on the fact that money is worth more now than in the future and dinishes future costs compared to holding that money as an investment until then. Using the discount rate that the IEA uses a cost in 30 years of 1 billion dollars becomes just $63m. Make it 60 years and the future decomissioning cost of a nuclear power plant is $3million dollars. Does that sound reasonable to you?

What do you think utilities do with the money set aside for decommisioning costs, Eponymous? Hide it under the matress?

Finrod, I strongly suspect, and I believe this was a recommendation/likely outcome from the Switkowski/UMPNER report, that the Government would underwrite the cost of decomissioning as part of the sweetener to encourage investment in nuclear.

Further, the Govt would definitely have to accept the insurance risk as part of the package.

Finrod, I strongly suspect, and I believe this was a recommendation/likely outcome from the Switkowski/UMPNER report, that the Government would underwrite the cost of decomissioning as part of the sweetener to encourage investment in nuclear.

Further, the Govt would definitely have to accept the insurance risk as part of the package.

Personally, I’d like a levy based on the pro-rata decomissioning and waste treatment cost to be levied on each unti of output. The costs of disposal deemed for each grade of waste sould be separated out, meaning that high level waste would be a lot more expensive than other grades of waste. There would also be a bond to cover liability for damage up to something like the Price-Anderson levels and also to cover the possible failure of the company to comply with the existing regulatory regime.

The money would be set aside in capital guaranteed funds controlled by a state-based trust

Should changes be required the company could be ordered to make them and if they were unable to do so, the state could step in and make the changes using the resources in the bond. The company would then have to repay the trust with interest. If it failed to do so, the plant could be forfeit and offerd through tender to others.

Once the plant reached its specified lifetime output — say 40 years at 90% CF — the decommissioning cost could be waived and they would pay the cumulative waste cost only. If the company chose to decommission the plant at this point then the decommissioning funds could be used by the company to support this or build a replacement plant.

Why is this discussion starting up on this thread that is intended as a summary of the threads under ‘Renewable Limits’? To avoid discupting the layout of BNC, can I suggest the authors of these posts move them to the current active thread, or perhaps Barry could open a new Open Tread. Perhaps autjhores could copy an paste their comments to the new thread and then Barry could delete the posts from here. The problem with opening a discussion here is not only does it distroy the purpose of this thread, but it also misses the wealth of other information. A new reader coming here would think that this is THE discussion thread on Renewable Limits. Thwe current discussion on this thread is just one tiny aspect of what has been discussed.

karen, those numbers come from Mark Diesendorf. He is saying that with 1000 MW of distributed wind, you’d need 250 MW of open cycle gas turbines to give a reasonable reliability. But at a typical capacity factor 30% for wind, about 300 MW of combined cycle gas turbine would give you all of the equivalent energy that the wind + OCGT would have delivered. So why the wind? It’s a bit of a tortured chain-of-reasoning — you may need to consult his “Sustainable Energy Solutions” book to try and understand Mark D.’s logic better. There is a lot of more detailed discussion on the topic of wind and gas backup on BNC — have a search of the archives and you’ll come up with a lot.

Wind power is slightly anticorrelated with the load for a warm climate like Australia, so you definately need close to 100% backup.

But that´s not even the million dollar question. After all, gas turbines cost relatively little to purchase. The million dollar question is how often do we have to use the gas turbines if we try to power entire countries with wind (as we must do if we are to solve the CO2 emissions problem). Getting 20% of our power from the wind is nice, but if it requires that the other 80% be mostly fossil to `back it up` (severe understatement) then it´s not going to cut the mustard.

300 MW of CCGT operating at 90% CF would generate 2365 GWh per year – almost the same as the wind. CF can probably be higher but not averaging 100%, so you might need ~335 MW of CCGT.

However, the CCGT has the (large) advantage of being always available (no energy storage required) and dispatchable.

The 1000 MW of wind can be made partly dispatchable by adding 250 MW of OCGT, to fill in for it when it is not generating. Mark Diesendorf is arguing that the other 50 MW of the wind are, statistically, ‘always available’ (the capacity credit, of 5% nameplate). So ‘only’ 250 MW of OCGT is needed.

If you want to look deeper at the issue, I suggest you read MD’s book.

oh, you’re not talking about the fuel required, your’e talking about the backup generator required.
sorry, it SOUNDED like you were saying wind power is not worthwhile because it takes the same amount of natural gas to provide the power with or without the wind! that is obviously ridiculous.
thanks.

Japan showed, that countries tend to have 20% reserve that they can switch on. (Japan lost over 30% nuclear and is still running…)

so 20% wind will not need any changes at all. 8and in a bigger network, like europe, the level is much much higher)

when a country reaches higher penetrations than 20%of wind, the situation changes fundamentally. at these these levels, wind will occasionally provide 100% of the required electricity. (a capacity factor between 20% and 30% means that you get 3 to 5 times this amount of power on certain times, possibly even nameplate capacity…)

any country moving above 20% will give a significant boost to storage technologies, as this means there is power at zero or even negative price, which storage can transform into pure money…

sod — We require reliable, on demand electricity and now also low carbon. So here is an exercise which deescribes in a simplified manner the problem faced by power planners.

Every day is exactly the same as the one before with regard to electricity requirements: from 6 am to 11 pm the grid requires 28 GW and from 11 pm to 6 am 20 GW. Using low carbon tecchnologies only [NPPs, wind, solar] design the least cost [LCOE basis] system of generators to service this demand while maintaining, most of the time, a 2 GW reserve. [Or 4 GW reserve if you insist.]

If one allows thermal storage on NPPs (I see no reason why not but nobody has actually built just as yet) the least cost is NPPs with thermal storage. Such a system can encourporate up to 29% solar PV [nameplate, so maximum of 8 GW] without difficulty. The solar PV component would, on average, generate about 5.8% of the power requirement. It turns out that more than that tends to become more expensive.

If indeed one has NPPs with thermal storage then some level of wind generation would indeeed lower costs if the cost of wind turbines and transmission is sufficiently low. Unfortunately, wind turbine LCOE is now beginning to rise due to mature technology, increased costs of materials, and the best sites are already occupied. My estimates of the LCOE for wind and for NPPs with thermal storage are such that no particular advantage can be found in using the wind resource, even with the nifty thermal stores to act as balancing agents.

However, I might have misestimated and it is rather a close call. Please try this exercise yourself.

The cost of storage is higher than the total levelized cost of gas fired electricity. No storage will be built, even if, as Sod, our sandbox economist, falsely contends, the power is free; in stead you now now have a 20% wind 80% gas grid.

`it SOUNDED like you were saying wind power is not worthwhile because it takes the same amount of natural gas to provide the power with or without the wind! that is obviously ridiculous.`

Karen, if you had read the main topic links, there are actually reports there of natural gas fired generation becoming less efficient from all the throttling, and also requiring more of the single cycle turbines that are more flexible to meet the wind variability but are less efficient than the combined cycles. I don´t believe all of it but it is something that few studies so far have included. It is certainly not as obvious and ridiculous as it might sound at first.

One of the things that has also not been considered is the natural gas leak rate through the turbine. You see, once you throttle combustion engines more, to accomodate varying wind loads, more fuel tends to get partially burnt and unburnt. For natural gas that is a problem, since it is a potent greenhouse gas. 70x as powerful as CO2 on a 20 year scale. Normally you´d lose 1 to 2% of the natural gas unburned through the engine. Even a 1% increase would be a major GhG issue.

Combine the lower gas burning efficiency with more natural gas unburned leak rate through the turbine, and the GhG gain could easily be marginal or even zero.

You are clearly more numerate than I. I was therefore wondering whether you could quantify the qualitative statements you made above in terms of CO2 equivalent emissions. In fact, I think it could be a very useful exercise to attempt to quantify all the statements below in an effort to assess the reality of the benefits promoted by the “the dash for gas” and “gas for wind balancing” enthusiasts.

1) One is typically told that CO2 emissions resultant from combustion for electric generation are halved when switching from black coal to gas. However, I doubt that methane leakage is accorded any CO2 equivalent value to add to the CO2 escaping in combustion exhaust gases when this claim is made.

2) I have read that long distance transmission of gas is, of itself, a very energy intensive activity, the CO2 emissions of which are not typically factored in when assessing the purported benefits of coal to gas switching. If long distance transmission is also associated with extra fugitive methane emissions, these should also be accounted for.

3) I have read that gas extraction from shale may also result in greater methane emissions than are typical for conventional gas extraction. If this is true, it is possibly of greater concern than possible ground water contamination and other factors that appear to receive most attention from those opposing shale gas development.

4) You have explained the efficiency losses associated with using gas to back up wind and explained that there are also likely to be increased fugitive methane emissions. You stated that ” even a 1% increase would be a major GhG issue.” Could you possibly combine both factors mentioned and come up with CO2 equivalent emissions to compare with the emissions figures normally quoted?

I am beginning to wonder whether Governments and their advisers are making wrong policy decisions because they are being misled by simple smokestack emissions figures when they ought to be considering “emission equivalent” figures. I am placing my faith in you, Cyril, to provide the ammunition necessary to allow them to make informed decisions!

Sod. There´s not enough pumped hydro capacity available on the scale to power the world with renewables. It is indeed a simple technology of which we don´t have enough.

We need at least 10 TWe of electrical flow for the world. Just one day of storage would be 240 TWh. It is insane. And one day is not enough. Even one week is tight, requiring considerable natural gas backup.

Power to gas is extremely inefficient. You lose 40% in the electrolyser, another 40% in the fuel cell or CCGT. Then there´s the compressor cost to store it somewhere underground. We´re down to just 33% cycle efficiency, meaning your wind and solar cost to produce the hydrogen and then use it in a fuel cell or CCGT triples your cost. That´s without taking into account the cost of the electrolyser, fuel cells, compressors,etc. No way you can compete with ordinary fossil natural gas, which costs 2 to 4 cents per kWh thermal delivered to a large industrial customer or powerplant.

You think we´re being pessimistic, Sod. But we´re really just being mathmatical. All the energy storage schemes are either way too inefficient leading to prohibitive costs, or are too high in capital cost leading to prohibitive costs. Please read the link I provided about a Nation Sized Battery.

Coal has a CO2 intensity of around 370 grams of CO2 per kWh. With the best available ultrasupercritical or IGCC plant, the net efficiency is 46%. This gives us 804 grams CO2 per kWh electrical. If all coal is burned to CO2 and not considering other lifecycle emissions.

Natural gas has a CO2 intensity of around 230 grams CO2 per kWh. For a 60% efficiency, best available CCGT, this makes 383 grams CO2 per kWh electrical. If all the methane is burned to CO2 and no efficiency loss from throttling, and other lifecycle GhG emissions are ignored.

That´s where it gets tricky. First we must estimate the efficiency lost from throttling a lot. At part load, the CCGT will run at 40 to 50% efficiency, but that is at steady state part load. Throttling itself loses efficiency especially with the steam bottoming cycle steam boiler spillage. But I´m being kind to natural gas and will assume 50% efficiency for the total duty for a heavy wind/gas grid. This makes the CO2 emission 460 grams per kWh.

Next it gets even more tricky. We need to estimate the methane leakage. Global warming potential for methane is shorter and more intense than CO2, so the period measured matters. Over a 20 year period it is 72x as powerful as CO2. Over a 100 year period it is 25x as powerful. Let´s be kind and use the 100 year number, bearing in mind that the methane component increases our risk of short term tipping points.

So your gas turbine leaks 1% it adds 25% to the CO2 emissions. For a 460 grams CO2 per kWh CCGT it becomes 575 grams-kWh

2% leak: 690 grams CO2 per kWh
3% leak: 805 grams CO2 per kWh.

Ergo, more than 3% leak makes state of the art gas in a wind grid backup function worse than state of the art coal baseload!

Now this gets pretty terrible pretty soon; methane is just such a powerful greenhouse gas. Worse, it is difficult to remediate via end of pipes solutions such as metal fibre oxidators (MFO´s which my company engineers and installs). The combustion range is just too narrow for this to be completely effective.

It´s not just about the turbine. At the well you lose some natural gas. Some is lost in compressors and piping it or making LNG out of it.

I talked to a gas engine engineer about this issue. He says a typical 1.5 percent leak rate through the engine is measured from the engines. But these are not gas turbines, they are reciprocating engines. I´m going to do some more digging later and bother some people with questions, but I don´t have any contacts in gas turbine companies.

Overall I´m estimating that 2% methane leak over the entire natural gas chain is probably on the low side.

It is true by the way that piping natural gas over large distances is inefficient. But for very long distances such as cross oceanic, LNG is used, which only costs 4 to 6% of the energy of the natural gas to liquify, if that comes from a CCGT then you add maybe 6 to 8% to the CO2 to the lifecycle emissions (but note that transporting coal probably has similar energy requirements so it won´t shift the relative performance much).

Total lifecycle emissions based on 1.4 percent leakage, 500 grams CO2 per kWh. But that assumes no effect from throttling efficiency and increased unburned methane from throttling. Though it provides some good base case numbers and already uses a lower efficiency that would fill in the throttling efficiency requirement.

One other thing to keep in mind is the NOx control that is used for CCGTs. They use ammonia in an SCR, it is an equilibrium reaction which requires constant operation… once you throttle this baby, the NOx emissions will go through the roof, there may even be considerable ammonia emissions. Yet something else to keep in mind when using gas turbines for wind backup….

Fantastic information that deserves to be much more widely known. I have read somewhere that 3% fugitive emissions from gas turbines are regarded as quite acceptable. Thus, judged over a 20 year time scale, gas is always going to be worse in global warming terms than efficient black coal combustion. Further, when used to back up wind in a high wind penetration scenario or when derived from shale or when conventional gas is converted to LNG and transported over long distances, it will be as bad as coal even on a 100 year basis.,

Thus, judged over a 20 year time scale, gas is always going to be worse in global warming terms than efficient black coal combustion. Further, when used to back up wind in a high wind penetration scenario or when derived from shale or when conventional gas is converted to LNG and transported over long distances, it will be as bad as coal even on a 100 year basis.

Yes, that’s an excellent conclusion. I really wish the natural gas sector would be more honest about their emissions and actually went to measure them. I think very few people of aware of just how critical the natural gas leak rate is to the natural gas GhG performance.

And, importantly, if we worry about short term tipping points, we should certainly not be pushing for any energy scheme based on methane.

I note in the first link Australia pledged to eliminate fuel subsidies at an international conference. Problem is 90% of countries including the worst offenders make the promise then don’t do anything.

CR point taken I’m thinking biogas which powers Swedish trains and the Audi e-gas system which appears to be 2-3 times the minimum cost of other fuels. Australia’s carbon cops have visited gassy coal mines to test for fugitive emissions from air shafts and open cuts. Presumably if the coal is going to China the methane is magically no longer a problem.

Biogas for trains is just nonsense. Trains the form of transportation easiest to electrify.

And the Audi e-gas project is not sustainable on a large scale, since the CO2 is derived from biomass. CH4 and CO2 are generated by anaerobic digestion. The CH4 will be fed directly into the gas grid, the CO2 will be captured and combined with H2 produced from the electrolysis of water to produce yet more CH4. In convetional anaerobic digesters, the CO2 is just vented. In the scheme proposed by Audi, CO2 capture and combination with H2 increases the total CH4 yield by roughly 25%. It’s a decent way to produce synfuels, but for future large-scale application, the CO2 would have to be derived from another source, for example by directly capturing it from the air. At the moment, what Audi does is little more than CNG greenwashing. It does not promote, large-scale sustainable mobility.

Following a BBC news item about Denmark’s aim for 100% renewable electricity (Link I see they pin their hopes on several factors. These include hydro swaps with Norway and no doubt feed-in tariffs but also more biomass burners along the lines of Avedore unit 2.

However I don’t see why apart from the high temperature supercritical ‘steam’ they won’t at some time have the same problems that recently befell Australia’s bagasse burning plants. That is drought or storms reducing the supply of ‘trash’ biomass so more expensive wood fuel has to be bought in. Some of the alkaline ash will return Ca but not enough K and P to the soil which needs supplementing. The crops also require a lot of Haber process fertilisers such as urea made from natural gas. That goes up in smoke as does the large amount of diesel that drives, tractors, harvesters and trucks.

When they cite impressive efficiency figures for biomass burning at Avedore they conveniently omit the indirect gas and oil input. A major drought could deny both straw fuel and Norwegian balancing hydro. If I recall Barry once calculated Danish electricity created over 500 kg (?) of CO2 per Mwh which will take a long time to reverse. Right now the Danes don’t think of themselves as big emitters in reality but trend setters in their imagination. That’s if it all goes to plan.

A solar panel on the roof of your car would only work during the day and would not produce enough power for the kind of acr you’d actually want to drive (and would produce less power when it is cloudy).

Remember that those solar powered car like objects that take part in races across the desert are super-lightweight single seaters with no air conditioning (and probably no crash safety either) and they require sunny weather to work.

well, I didn’t think I had to power a whole civilization from one roof, but is that the only reason not to go solar? okay.
btw, today’s electric car actually does have extra seats and air conditioning. it’s not nuclear physics!MODERATOR
Hi Karen – thanks for your comment. Just a reminder that all discussion on BNC has now moved to the BNC Discussion Forum, so it is better to use that now, as you are more likely to get a reply. You are able to start your own topics, if you wish, so asking more about solar power over on the forum might be a good idea. Click on the Forum tab at the top of the page or on the left sidebar link. See you over there:)